Hydrogen sulfide is often present in drilling formations and is a by-product of some chemical processes. Wherever encountered, it is a contaminate that must be eliminated.
Hydrogen sulfide encountered in drilling oil or gas wells may be dangerous or even deadly. It may be scavenged by additives to the drilling mud. One such additive and the process of using it is disclosed in U.S. Pat. No. 4,008,775.
In my co-pending application, Ser. No. 06/221,897, it is disclosed that such an additive may be added directly to hydrocarbon oil contaminated by hydrogen sulfide, the scavenging taking place in the oil without any other medium.
The additive so utilized is a unique iron oxide particle characterized by an Fe.sub.3 O.sub.4 crystalline phase but including an amorphous Fe.sub.2 O.sub.3 moiety; on reaction with hydrogen sulfide an environmentally safe reaction product is formed which is substantially acid stable. The reaction product is non-magnetic, whereas the unreacted particles are attracted to a magnet. When used as a drilling mud additive, the extent to which the particles have been exhausted has been monitored by magnetic differentiation.